Compare products

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond readOnlyHint/openWorldHint, the description discloses a real output behavior: the cheapest product is marked, but only when all inputs share one currency. That conditional is genuinely useful context an agent could not get from the annotations. It still omits what happens on mixed currencies or output shape.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, no filler, with the core scoping constraint and the cheapest-marking behavior front-loaded. Every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only, no-output-schema tool whose annotations already cover the safety profile, the description covers the essentials plus the currency condition. The gap is the unexplained `sub_id` parameter, which is the main reason this is not a 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full parameter burden. It explains that `refs` are product references limited to 2–5 (though the bounds already live in the schema) but says nothing about `sub_id` or its format, leaving one of two parameters entirely undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Side-by-side data for 2–5 products') and the identifier used ('by `ref`'), which is enough to distinguish it from search_products at a glance. It does not explicitly name the sibling it complements, so differentiation is implicit rather than stated.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The comparison intent is implied by the name and description, but there is no explicit when-to-use trigger, no prerequisite (e.g. obtaining refs from search_products first), and no mention of when not to use it. Adequate but inferential.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.